A known seat slide device includes a lower rail fixed on a vehicle floor and an upper rail positioned so as to be slidable on the lower rail. In this configuration, a seat is fixed on the upper rail.
In order to smooth the movement of the upper rail sliding on the lower rail, a bearing is provided between the upper rail and the lower rail. Specifically, the bearing is supported by the upper rail so as to rotate on the lower rail.
Further, the seat slide device includes a lock and unlock mechanism for locking (engaging) and unlocking (disengaging) the upper rail, to which the seat is fixed, relative to the lower rail.
Specifically, the lock and unlock mechanism includes a main lock plate, which is comprised of a hook portion and a main body.
More specifically, the hook portion is normally biased by means of a spring so as to engage with a lock hole formed on the lower rail, and the main body is moved by means of an operation handle in an unlocked direction against the biasing force from the spring.
The hook portion is integrally formed on the main body at a lower end portion thereof, and the operation handle is provided so as to press down an upper end portion of the main body.
In such configuration, a pair of bearing is supported by the upper rail so as to slide on a bottom portion of the U-shaped lower rail, and a space is provided between an upper portion of the lower rail and each of the bearings. This space may cause a rattling, especially vibrations of the upper rail against the lower rail in a vertical direction.
JP10-100752A discloses a seat slide in which a pair of wedge stoppers is inserted between the upper portion of the lower rail and the bearing while the upper rail is locked with the lower rail so that the rattling of the upper rail against the lower rail is reduced.
However, in order to insert two stoppers around the bearings provided both sides of the lower rail at the same time, the seat slide device needs to be configured accurately, and the stoppers need to be operated precisely. This makes the device unpractical. Thus, a need exist for the seat slide device to reduce the rattling of the upper rail against the lower rail in practical ways.